E=mc2

So this old guy comes in, stumbles over a chair, almost over the dog, catches himself (I’m thinking, “Oh, great!”, and says to me in German, “I’m Albert Einstein. Are you a mathematician?” Fortunately I speak German like a native. So I explained that we’re not mathematicians, that we do mechanical and bodywork and painting on all domestic and foreign cars and trucks, and we’re been doing that for more than 50 years in the same location, and then I said, “why do u need a mathematician?” He says, “ I can’t figure something out. If E is the energy of an object, and m is the mass at rest, and c is the speed of light — what is gamma?” So I tell him, “Gamma depends on velocity, and mass, like gamma,grows with velocity. So as the object approaches the speed of light the mass approaches infinity. And as we know from the A-bomb, a small mass can can release and extraordinary amount of energy. So from the Taylor expansion in calculus — “ He interrupts me. “ Yes, yes, I know that, but how can I sum it up?” I thought for a moment. “How about E=mc2?” His jaw dropped and he stared at me. “Ach, du lieber!” He shouted. “That’s it! That’s it! E=mc2!” And he rushed out. Wonder if he ever used the formula.